Portable flame photometer and sampling probe

ABSTRACT

A hand-held sampling probe remotely connected to a portable flame photometer enables immediate on-site identification of a desired piece of steel in a mixed stockpile thereof according to a percentage concentration of manganese element in the steel. An operator causes the sampling probe to strike a low-voltage electric arc on a sampling surface of the test piece so as to generate an aerosol of atmospheric air and sample particles. An induction burner located in the flame photometer is fueled by a self-contained propane bottle and is adjusted to aspirate the aerosol and excite the sample particles in low-energy flame. Photoelectric circuits analyze the flame spectra and accumulate concentrations of iron as an internal standard and manganese as the identifying element. When the iron concentration reaches a predetermined value, a control unit interrupts the electric arc and element accumulations and displays percent manganese concentration on a meter without ratioing iron and manganese signals.

United States Patent 1191 Cody et al.

1451 Feb. 12, 1974 PORTABLE FLAME PHOTOMETER AND SAMPLING PROBE [75]Inventors: Thomas E. Cody, Allentown, Pa.;

Arthur L. Davison, Saugus, Calif.; Joseph A. Grohowski, Bethlehem; GezaJ. Horvath, both of Bethlehem, Pa.; Theodore R. Linde, Coopersburg, Pa.

[73] Assignee: Bethlehem Steel Corporation,

Bethlehem, Pa.

22 Filed: Mar. 21, 1973 21 Appl. No.: 343,305

Primary Examiner-Ronald L. Wibert Assistant Examiner-V. P. McGraw 5 7ABSTRACT A hand-held sampling probe remotely connected to a portableflame photometer enables immediate on-site identification of a desiredpiece of steel in a mixed stockpile thereof according to a percentageconcentration of manganese element in the steel. An operator causes thesampling probe to strike a low-voltage electric are on a samplingsurface of the test piece so as to generate an aerosol of atmosphericair and sample particles. An induction burner located in the flamephotometer is fueled by a self-contained propane bottle and is adjustedto aspirate the aerosol and excite the sample particles in low-energyflame. Photoelectric circuits analyze the flame spectra and accumulateconcentrations of iron as an internal standard and manganese as theidentifying element. When the iron concentration reaches a predeterminedvalue, a control unit interrupts the electric arc and elementaccumulations and displays percent manganese concentration on a meterwithout ratioing iron and manganese signals.

15 Claims, 5 Drawing Figures PORTABLE FLAME PHOTOMETER AND SAMPLINGPROBE BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates broadly to spectrometric apparatus. More particularly,the invention concerns portable spectrometric apparatus capable of beinghandcarried by an operator to a test site for immediately identifying aparticular type of test piece in a mixed stockpile of piece materialssuch as steel or other electrically conductive materials.

2. Description of the Prior Art In the primary steel industry, as wellas many steeluser and other metal industries, there has been a longstanding problem of providing a rapid and reliable onsite method ofidentifying mixed steels and other metals, and to use unskilledpersonnel in the identifying procedure. That is, identifying the grade,or at least two elements of composition, of unmarked steel or othermetal bars, billets, plates and the like in a mixed stockpile thereoflocated almost anywhere, and to use personnel having little testingskills.

Heretofore, one common on-site method of identifying mixed steels, forexample, involved the well-known spark test. In this test, a highlyskilled operator carefully applies a high speed grinder to a test piecewhile visually analyzing the character of the resulting spark pattern.Identification is'based upon determining the amount of carbon in thetest piece which produces a known characteristic spark pattern, and tothe amount of a limited number of additional elements consisting ofmolybdenum, nickel, silicon and/or tungsten which vary the sparkpatterns. Test accuracy and reliability vary widely because of thedifferent skills of different operators and variations in testenvironmental conditions.

Another method of identifying mixed steels is the well knownspectrochemical analysis procedure. Here a sample is physically removedfrom a steel test piece at a site somewhere in a plant facility,identified and transported to a remotely located laboratory, andprepared and analyzed on a spectrometer by a skilled operator. Thismethod normally provides an accurate and complete analysis of complexsamples, whereas identification of the test piece usually may be made onthe basis of iron and only one other element. However, the spectrometerwhile accurate is immobile, is costly in terms of capital equipment,operation, maintenance, and has inherent delays in identifying a testpiece at the plant site.

Some improvement in the spectrochemical analysis method is shown in U.S.Pat. No. 3,602,595 to Dahlquist et al. This patent teaches a method andapparatus for generating a sample aerosol by high voltage electric arcin a typical sampling chamber which has been remotely located a limiteddistance away from the remaining portions of an otherwise conventionallaboratory spectrometer and sealably affixed to a prepared surface of atest piece. The electric arc disrupts sample particles from the surfaceof the test piece after presparking said surface. A pressurized sourceof argon is required as both an inert arc-supporting gas in the samplingchamber and as an inert carrier gas in the aerosol for transporting thesample particles to the spectrometer for analysis. Dahlquist et al. havethe advantage of providing limited on-site sampling, and thereforeminimize sample transport time, but have all the other attendantdisadvantages in identifying a test piece as noted above for thelaboratory spectrochemical analysis method.

SUMMARY OF THE INVENTION One of the objects of this invention is toprovide improved spectrometric apparatus that substantially overcomesthe prior art disadvantages.

Another of the objects of this invention is to provide portablespectrometric apparatus capable of being hand-carried to a test site andimmediately identify a particular type of test piece in a mixedstockpile of piece materials.

Another object of this invention is to provide low cost portablespectrometric apparatus requiring little or no sample surfacepreparation, having a minimal number of components, being easy tooperate and maintain by unskilled personnel, yet enable rapid andreliable identification of mixed materials on a site'located almostanywhere.

The foregoing objects are obtained with portable spectrometric apparatusconsisting essentially of a hand-held sampling probe remotely connectedto a hand-carried portable flame photometer which, in the case ofidentifying mixed steels, is adapted to analyze the test piece for iron(Fe) as an internal standard and manganese (Mn) as an identifyingelement. This is because these elements are always present in steelcompositions but were unable to be recognized in the prior art by thespark testing procedure noted above. In the present apparatus, anunskilled operator causes the sampling probe to strike a low-voltageelectric arc on a sampling surface of the test piece so as to generatean aerosol of atmospheric air and sample particles. An induction burnerlocated in the flame photometer is fueled by a self-contained propanebottle and is adjusted to aspirate the aerosol and excite the sampleparticles in a low-energy flame. Photoelectric circuits analyze theflame spectra and accumulate concentrations of iron and manganese andwhen the iron concentration reaches a predetermined value, a controlunit interrupts both the electric arc and element accumulations anddisplays percent manganese concentration on a meter without ratioingiron and manganese signals to identify a particular test piece.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an illustration of theportable spectrometric apparatus of the present invention showing thehandheld sampling probe attached to a billet test piece and connected byway of a flexible hose and electric cable to the portable flamephotometer, the latter being shown mostly in vertical cross-sectionvFIG. 2 is a longitudinal cross-section of the sampling probe used in thepresent invention.

FIG. 3 is a vertical cross-section of an induction burner used in theportable flame photometer used in the present invention.

FIG. 4 is a horizontal cross-section of the upper portion of the flamephotometer showing the location of electro-optical components inrelation to the flame of the induction burner.

FIG. 5 is a schematic diagram of the present invention including themeasuring and control circuits involved in the spectrometric analysis ofa test piece.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings,particularly FIG. 1, the portable spectrometric apparatus of the presentinvention is capable of identifying test piece as a steel billet havinga desired percent manganese (Mn) concentration when among a mixedstockpile of billets having various percentages of manganeseconcentrations and the stockpile is located on a site almost anywhere,it being understood that all desired billets have a predeterminedpercent iron (Fe) concentration as an internal standard element. Theportable spectrometric apparatus consists essentially of combininghand-held sampling probe 11 by way of remote connections to hand-carriedportable flame photometer 12. This combination of apparatus is adaptedto permit one unskilled operator to rapidly and reliably identify billet10 while carrying said apparatus at or around test site.

Hand-held sampling probe 11 is detailed in FIG. 2 and is adapted to bebrought into contact with testpiece sampling surface 13, and furtheradapted to strike a low-voltage electric are 14 on a sampling surface 13in atmospheric air when powered from an external source. The arcingcauses generation of sample aerosol 15 which consists of atmospheric airas a carrier and sample particles disrupted from sampling surface 13 bythe electric arc. Aerosol generation is accomplished without grinding,pre-sparking or otherwise preparing sampling surface 13 as is done inthe aforementioned prior art apparatus.

Sampling probe 11 includes hand-held probe housing 16 which is a hollowcylinder made of electrically insulating material such as commerciallyavailable synthane. Probe housing 16 is provided with support legs 17and 18 at one end thereof and an atmospheric air space 19 between saidlegs. A circular brass support plate 20 having central opening 21 isformed with flanges 22 and 23 adapted to be screw-attached to legs 17and 18.

Sampling probe 11 also includes annular electrode 24 which is connectedmechanically and electrically to brass support base 20 and functions asthe probes base. Annular electrode 24 is fabricated having a relativelysmooth contact surface 25, axial cylindrical opening 26 and lateralchannel opening 27 across contact surface 25, both said openingsenabling passage of atmospheric air therethrough. Contact surface isadapted to be detachably mountable on sampling surface 13 in such manneras to provide a good electrical contact therewith. When billet 10 ismade of steel, a commercially available alnico permanent magnet havingthe prerequisite configuration is a preferred structure for annularelectrode 24, otherwise, almost any hard electrically conductingmaterial may be used.

The alnico magnet has the advantages of providing a detachably mountablecontact structure having sufficient pulling forces through contactsurface 25 and sampling surface 13 to maintain substantially uniformelectrical conductivity between electrode 24 and billet 10 duringtesting, as well as to hold the base of sampling probe 11 at the samesampling site throughout a test, both without requiring seals or othermechanical means coacting between probe 11 and billet 10 as in the priorart. This arrangement is a factor which enables hand-held sampling probe11 to generate sample aerosol 15 under uniform sampling conditions in anatmospheric air environment, thereby contributing to the reliableoperation of the portable spectrometric apparatus of the presentinvention.

Inasmuch as annular electrode 24 is designed to 5 contact samplingsurface 13, it is intended that sampling surface 13 function as acathodic source when electrode 24 is connected to a negative source ofdirect current as will be mentioned below. For this reason, annularelectrode 24 will hereinafter be referred to as annular cathode 24, eventhough it is not intended to be a cathodic source in the usual sense.

Also included in sampling probe 11 is movable hollow electrode 28 whichis adapted to be connected externally not only to a positive source ofdirect current for cooperating with cathode 24 in the production ofelectric arc 14, but also to portable flame photometer 12 fortransporting sample aerosol 15 away from the billet sampling surface 13where the aerosol is generated. Therefore, electrode 28 will hereinafterbe referred to as movable hollow anode 28. Anode 28 is a hollow metaltube of copper, for example, which is slidably supported coaxiallywithin probe housing 16 by electrically insulated front and rear supportassemblies as shown in FIG. 2 and described below. Hollow anode 28 isprovided with anode tip 29 having an end cut parallel to the annularcathode contact surface 25 and insulated from cathode 24 only byatmospheric air in axial opening 26. This enables a ring-shaped electricare 14 to be struck in atmospheric air between anode tip 29 and billetsampling surface 13. Sample particles are disrupted from surface 13 byarc 14 and mixed with atmospheric air to form sample aerosol 15, thelatter flowing away from sampling surface 13 through the interior ofhollow anode 28.

Heat generated by electric are 14 may be dissipated from anode tip 29 bysecuring finned aluminum heat sink 30 to anode 28,- near tip 29 and inatmospheric air space 19 of probe housing 16. This will improve thesampling probe 11 duty cycle and increase the rapidity with whichaerosol samples 15 may be made.

The front support for tubular anode 28 is provided by support member 31which is made of nylon, for example, and screw-attached to probe body 16near the beginning of legs 17 and 18. A threaded, shouldered, brassbushing 32 is located centrally through support member 31 and boredsuitably for guiding anode 28 movement axially while providing a slidingelectrical contact from anode 28 to external wiring.

The rear support for tubular anode 28 consists of rear support assembly33 which may also be made of nylon. Rear support assembly 33 includesgap adjusting screw 34 having an axial bore 35 therethrough. Axial bore35 is sized at one end to slidably support therein an exterior end oftubular anode 28. The exterior portion of gap adjusting screw 34 isadapted with threaded shank 36 at the anode support end, wrenching flats37 in the middle, and hose attachment fitting 38 at the other end. Rearsupport assembly 33 also includes threaded support member 39 whichsupports gap adjusting screw 34 from probe housing 16 by way of screwattachments. A threaded locknut 40 with wrenching flats 41 is providedfor locking gap adjusting screw 34 to support member 39 at apredetermined position as noted below.

Axial movement of anode 28 to bring anode tip 29 into contact withsampling surface 13 is caused by an operator pushing start button 42axially toward the sampling surface. Start button 42 includes shank 43which is constrained to movement in probe housing slot 44. Set screw 45has one end anchored in shank 43 and the other end screwed throughinsulated collar 46 into anode 28 so as to transmit the operators axialforce from starting button 42 into anode 28. A compression type biasingspring 47 surrounding anode 28 applies a biasing force against one sideof collar 46 to move the other side of collar 46 against gap adjustingscrew 34. This force also acts on anode 28 to move anode tip 29 into anarc sustaining" position, the position shown in FIG. 2. While in thisposition, a gap of about 1.2 mm. between anode tip 29 and billetsampling surface 13 should be attained. If such is not the case, theproper gap can be attained by proper adjustment of gap screw 34.

Electrical service between sampling probe 11 and portable flamephotometer 12 is provided by flexible multi-conductor cable 48.Conductors 49 and 50 in this cable connect anode 28 at bushing 32, andcathode 24 at brass plate 20, to respective external positive andnegative direct current sources. Conductors 51 and 52 connect resetswitch 53 in sampling probe 11 to control circuitry in photometer 12. Aswill be explained below, reset button 54 is pressed before pushing thestart button 42.

The sample aerosol generated by electric are 14 being struck at samplingsurface 13 is transported from anode tip 29 through anode 28 and hosefitting 38 to portable flame photometer 12 by way of a flexible rubberhose 55.

Hand-carried portable flame photometer l2 aspirates sample aerosol 15over hose 55 by means of a built-in induction burner where sampleparticles are excited to a light-emitting level. Light emitted at twoselected portions of a spectra corresponding to iron and manganese aredetected, analyzed and displayed on a Percent Manganese Mn) meter byself-contained electrooptical components. The meter reading is retaineduntil an operator depresses reset button 54 on sampling probe 11,thereby preparing the spectrometric apparatus for the next sample andanalysis.

Portable flame photometer 12 includes ventilated housing 56 shown inFIGS. 1 and 4 as having a carrying handle 57, supporting legs 58, and anequipment mounting shelf 59 located midway across housing 56, therebyestablishing upper and lower compartments in housing 56. The right end60 of housing 56 is adapted to be hinged along vertical hinge 61 at therear of housing 56 to provide access to components in the upper andlower compartments. A flame compartment 62 is established bysub-dividing the right end of the upper compartment with flame barrier63, and by attaching chimney 64 on top of an opening in the top of rightend 60 of said housing. Chimney 64 includes baffles 65 and 66 to preventdirect exposure of personnel to an internal flame, as well as to preventexterior radiant energy such as ambient light from entering flamecompartment 62.

Portable flame photometer 12 also includes induction burner 67 asdetailed in FIG. 3. Induction burner 67 is located in the right end 60of housing 56, midway between the upper and lower compartments, andconsists of a modified brass utility burner assembly which includesparts supplied by Bernzomatic Corp. from their model No. JT680CMaxi-Jet-Torch" burner. In-

duction burner 67 comprises fuel inlet 68, Bernzomatic Corp. fuelmetering orifice 69 having an 0.006 inch dia. opening located in fuelinlet 68, a Bernzomatic Corp. venturi intake system 70 consisting ofbody 71 having air inlet openings 72 located just above orifice 69, andan axially located venturi 73, a flame attenuator 74 mounted to venturibody 71 and extending above and below the discharge end of body 71, anda flame diffuser screen 75 and screen cap 76 secured to the upper end offlame attenuator 74.

The Bernzomatic Corp. venturi intake system 70 is modified by providinga brass air inlet 77 completely surrounding air intake openings 72. Airinlet 77 ineludes hose fitting 78 for attaching rubber hose 55 theretoso that substantially all of the combustionsupporting air required forburner 67 is supplied by the atmospheric air in the sample aerosol 15generated by sampling probe 11. A small air bleed hole 79 is located inthe wall of hose fitting 78 to prevent burner flame 80 from beingextinguished when anode tip 29 is caused to momentarily contact samplingsurface 13 during the striking of electric are 14. Although not shown onthe drawings, air bleed hole 79 may alternatively be located in anode 28near anode tip 29 for the same purpose.

Flame attenuator 74 is located in a hole in shelf 59 and held there bycollar 81 so that the upper portion of induction burner 67 will belocated in flame compartment 62. Collar 81 is adjusted vertically sothat the blue cones of flame 80 are adjusted to be about one-eighth inchbelow the lower edge of aperture 82 in the wall of flame barrier 63. Anadditional collar 81 (not shown) may be located beneath shelf 59 ifdesired.

Induction burner 67 is fueled preferably from a Bernzomatic Corp. ModelNo. Tx-9 pressure-bottled propane source 83 removably mounted in thelower compartment of flame photometer housing 56. Bernzomatic Corp.Model No. AT-5621 pressureregulator/shut-off valve 84 is detachablyconnected to propane source 83 and preset to regulate the propanepressure to about 26 psi while flowing through braided rubber hose 85 toburner fuel inlet 68. Valve 84 is so adjusted that flowing propaneaspirates sample aerosol 15, by way of hose 55 and burner air inlet 77then mixes with aerosol atmospheric air in venturi intake system 70 tosubsequently produce a low-energy flame 80. Flame 80 excites sampleparticles in aerosol 15 to a level where a spectra of radiant energy 86is emitted which represents iron, manganese, and other elements, in acontinuum having a low background in the manganese region. It is to benoted that propane is a preferred fuel for producing the low-energyflame, as well as the resulting low-background continum, because thispermits a simplified electro-optical arrangement for analyzing spectra86.

The electro-optical components used to analyze the spectra of radiantenergy 86 are shown schematically in FIG. 5 and are physically locatedin portable flame photometer 12 generally as shown in FIGS. 1 and 4.These components include photomultiplier (PM) tubes 87 and 88 designatedFe" and Mn" respectively, and mounted on shelf 59 in light detectingcompartment 89, the latter being established by placing light barrier 90in the left end of the upper compartment of photometer housing 56. Lightbarrier 90 includes apertures 91 and 92 for imaging spectra 86 onrespective photocathodes in the Fe and Mn PM tubes 87 and 88. Lightshields 93 and 94, each having an image window, are

placed over PM tubes 87 and 88 in alignment with apertures 91 and 92,respectively.

Mounted on the window of light shield 93 is an Fe optical filter 95designed to permit PM tube 87 to be responsive to light from spectra 86only in a range from 5,650A to 5,-75OA. In addition, mounted on thewindow of light shield 94 is an Mn optical filter 96 designed to permitPM tube 88 to be responsive to light from spectra 86 only in a rangefrom 4,022A to 4,038A. PM tubes 87 and 88 have output signalsproportional to the amount of iron and manganese, respectively, insampling surface 13 of the billet 10 being tested. The actual magnitudeof these output signals is governed by the density of opticalcomponents, and to PM tube sensitivity to light at various wavelengths.PM tube sensitivity is determined by the amount of high voltage DCapplied to each PM tubes string of dynodes.

Additional electronic components are mounted in the lower compartment ofphotometer housing 56, mainly on printed circuit board 97. Included insuch components is low-voltage DC source 98 which is shown only in FIG.5, said source being a conventional constant-current type havingpositive and negative output terminals connected to anode 28 and cathode24 in sampling probe 11 by way of conductors 49 and 50, respectively,said conductors being contained in electric cable 48. Source 98 isdesigned to maintain a 2.8 ampere current flow from anode 28 throughsampling surface 13 to cathode 24, the voltage normally varying fromabout 35 to about 50 volts DC depending upon the instantaneous sampleconductivity between anode "28 and cathode 24. Another DC source (notshown) is provided to power the electronic analyzing circuits describedbelow. In addition, a conventional high-voltage DC source 99, which isshown only in FIG. 5, is adapted to 1,500 a 1500 volt DC source for thedynode strings in PM tubes 87 and 88. It is to be noted that all of theabove-noted DC sources may be designed to be powered from either aself-contained battery pack (not shown) locatable in photometer housing56, or from an external AC source (not shown).

Potentiometers 100 and 101 are provided to adjust the high voltage DCfrom source 99 to the dynode strings in PM tubes 87 and 88 to betweenabout 600 v. and about 1,100 v. The particular value depends upon thesensitivity required to cause the output signals of PM tubes 87 and 88to achieve a predetermined ratio when billet 10 contains known amountsofiron as internal standard and manganese as an identifying element.

However, it is to be understood that the output signals from PM tubes 87and 88 are not actually ratioed during normal operations of the presentspectrometric apparatus.

Referring now to FIG. 5, the output signals from PM tubes 87 and 88 willhereinafter be referred to as the Fe signal and the Mn signal,respectively. Both of these signals are fed to control unit 102 whichconsists simply of a few conventional logic devices, such as relays,arranged to control the program sequence of analysis of the Fe and Mnsignals. Control unit 102 directs the Fe signal to an Fe accumulator 103and the Mn signal to an Mn accumulator 104, both signals being groundedinitially for a short time delay as noted below. In both accumulators103 and 104, the respective Fe and Mn signal charges an input capacitorand the accumulated charge is amplified by an operational amplifiertherein.

The amplifier in Fe accumulator 103 has an output signal which is fed tocomparator where it is compared to a reference signal from adjustablereference voltage source 106, said reference voltage representing apredetermined percent concentration of iron to be had in a test piece.Simultaneously, the amplifier in Mn accumulator 104 has an output signalwhich is fed through control unit 102 and scaling potentiometer 107 toMn meter 108, thereby providing an indication of the accumulatedconcentration ofmanganese in steel billet 10. Prior to analyzing billet10, potentiometer 107 is adjusted to calibrate Mn meter 108 over a rangeof about 0.l percent at a point slightly above zero to 2.0 percent atfull scale with known metal standards.

Current flow for electric are 14 is sensed in low voltage DC source 98and a current flow control signal is fed to time delay device 109 tosignify that electric arc 14 is generating sample aerosol 15. After apredetermined time period, which corresponds to the time needed tocleanse hose 55 and transport sample aerosol 15 to be aspirated fromsampling probe 11 to induction burner 67, time delay device 109 causescontrol unit 102 to remove the ground from the Fe and Mn signals asnoted above and permit the capacitors in Fe and Mn accumlators 103 and104 to begin charging. When the accumulated Fe signal exceeds thereference signal from source 106, then comparator 10S signals controlunit 102 to interrupt capacitor charging in accumulators 103 and 104, tointerrupt the current flow from low-voltage source 98 to sampling probe1 1 so as to terminate electric are 14, and to hold the Mn meter 108reading to indicate the percent concentration of manganese in steelbillet 10.

The percent manganese concentration reading will be retained on meter108 until the operator presses button 54 on reset switch 53. This causescontrol unit 102 to discharge the capacitors in Fe and Mn accumulators103 and 104, to restore meter 108 to its low point, to simultaneouslyground the Fe and Mn signals from PM tubes 87 and 88, and restore thespectrometric apparatus to an initial condition prior to the operatorpressing start button 42 to begin another sampling test.

We claim:

1. In spectrometric apparatus for identifying a conductive test piece byanalyzing a sample aerosol having sample particles with known elementalcharacteristics, the improvement consisting essentially of a samplingprobe comprising:

a. a cylindrical probe housing made of electrically insulating materialand provided with an atmospheric air opening at one end thereof,

b. a cathode mounted at the open end of said probe housing, said cathodeincluding an axial air space and further including an end surfaceadapted to contact a sampling surface of said test piece, and

a. a hollow anode located in said probe housing and adapted to cooperatewith said cathode to strike a low-voltage electric arc in atmosphericair on said sampling surface, thereby generating a sample aerosolconsisting of atmospheric air and arcdisrupted sample particles, saidaerosol withdrawn through said hollow anode for subsequent analysis.

2. The apparatus of claim 1 wherein said probe housing includes meansassociated with identifying the test piece.

3. The apparatus of claim 1 wherein said cathode is a magnet whichenables the sampling probe to be detachably mounted to test pieces withmagnetic properties.

4. The apparatus of claim 1 wherein said cathode includes an airpassageway disposed laterally across the said end contact surface.

5. The apparatus of claim 1 wherein said anode is adapted to be moved insaid probe housing to momentarily contact said sampling surface.

6. The apparatus of claim 5 wherein said anode is further adapted to bebiased and subsequently withdrawn from the sampling surface to anarc'sustaining position.

7. The apparatus of claim 1 wherein said anode further includes a heatsink affixed thereto in the region of the open air space in saidhousing.

8. The apparatus of claim 1 including:

d. means including conductors for connecting said anode and cathode to asource of electric current and a hose for conducting said sample aerosolaway from said sampling probe.

9. spectrometric apparatus for identifying a conductive test piece,comprising:

a. a hand-held sampling probe comprising:

.1 a cylindrical probe housing made of electrically insulating materialand provided with an atmospheric air opening at one end thereof,

.2 a cathode mounted at the open end of said probe housing, said cathodeincluding an axial air space and further including an end surfaceadapted to contact a sampling surface of said test piece, and

.3 a hollow anode located in said probe housing and adapted to cooperatewith said cathode to strike an electric arc in atmospheric air on saidsample surface, thereby generating a sample aerosol consisting ofatmospheric air and arcdisrupted sample particles having known elementalcharacteristics, said aerosol withdrawn through said hollow anode forsubsequent analysis, and

.4 means including electrical conductors for connecting said anode andcathode to an external source of electric current, and further includinga hose for conducting said sample aerosol away from the hollow anode insaid sampling probe, and

b. flame photometer means connected to means 9.a.4 and adapted toprovide said electric arcing current to said sampling probe, and furtheradapted to aspirate said sample aerosol by means of a selfcontainedinduction burner, said photometer means including photoelectric meansfor analyzing the burner flame to determine the concentration of aplurality of known elements in said sample particles, and furtherincluding means for indicating the concentration of at least one saidelement to identify said test piece.

10. In spectrometric apparatus for identifying test material bygenerating a sample aerosol having sample particles with known elementalcharacteristics and then analyzing said particles, the improvementconsisting essentially of flame photometer means comprising:

a. a housing having an upright chimney, b. a pressurized bottle ofgaseous fuel in said housing,

c. an induction burner located in said chimney and adapted to aspiratesaid sample aerosol from its source while burning said fuel, said burneradjusted to excite sample particles in a flame and emit a spectra ofradiant energy representing a plurality of known elements in said sampleparticles,

d. photoelectric means for analyzing said spectra dur ing a single testto produce separate element signals corresponding to the accumulatedconcentration of an internal standard element and at least oneidentifying element,

e. control means receiving said separate element signals and acting onsaid photoelectric analyzing means to interrupt the concentrationaccumulation of each said identifying element whenever said internalstandard element concentration accumulates to a predetermined value, and

f. means for utilizing at least one interrupted identifying elementsignal to identify said test material without directly comparing theinternal standard signal with an identifying element signal.

11. The apparatus of claim 10 wherein said control means includes timedelay means acting on the photoelectric analyzing means for delaying theanalysis of flame spectra for a period corresponding to the timerequired to transport said sample aerosol from its source to saidinduction burner.

12. The apparatus of claim 10 wherein said test material is steel andsaid photoelectric analyzing means is adapted to accumulate theconcentration of iron as said internal standard element.

13. The apparatus of claim 10 wherein said test material is steel andsaid photoelectric analyzing means is adapted to accumulate theconcentrations of iron and manganese as said internal standard elementand one of said identifying elements respectively.

14. Portable spectrometric apparatus for on-site identification of aconductive test piece, comprising:

a. sampling probe means including an anode and cathode adapted to strikean electric are on a sampling surface of said test piece and generate asample aerosol having arc-disrupted sample particles with knownelemental characteristics, and

b. portable flame photometer means comprising:

.1 a hand-carried housing having an upright chimney,

.2 a source of arcing current connected to the anode and cathode in saidsampling probe means,

.3 a pressurized bottle of gaseous fuel in said housing,

.4 an induction burner located in said chimney and adapted to aspiratesaid sample aerosol from the sampling probe means while burning saidfuel, said burner adjusted to excite sample particles in a flame andemit a spectra of radiant energy representing a plurality of knownelements in said sample particles,

.5 photoelectric means for analyzing said spectra during a single testto produce separate element signals corresponding to the accumulatedcon- .6 control means receiving said separate element signals and actingon said photoelectric analyzing rial without directly comparing theinternal standard signal with an identifying element signal.

and

b. portable flame photometer means comprising:

.1 a hand-carried housing having an upright chimney,

means to interrupt the concentration accumula- ,2 a Source f arcing r tco ne ted to the tion of each said identifying element whenever anode dca h de in said sampling probe said internal standard elementconcentration acmeans,

cumulates to a predetermined Value, and .3 a pressurized bottle ofgaseous fuel in said hous- .7 means for utilizing at least oneinterrupted idening tifying element signal to identify said test mate-.4 an induction burner located in said chimney and including a fuelinlet connected to said fuel source, and an air inlet connected to thehollow 15. Portable spectrometric apparatus for on-site identificationof a conductive test piece, comprising:

a. hand-held sampling probe means comprising: 5

.l a cylindrical probe housing made of electrically anode in saidsampling probe, said burner adapted to aspirate the sample aerosol andobtain substantially all of the combustion supportinsulating materialand provided with an atmospheric air opening at one end thereof, .2 acathode mounted at the open end of said probe ing gas for burning saidfuel from atmospheric air in said aerosol, said burner adjusted toexcite sample particles in a flame and emit a spectra of radiant energyrepresenting a plurality of known housing, said cathode including anaxial air space l t l l and further including an end surface adapted toe emen S m a Samp e par le Contact a Sampling surface of Said test pieceand .5 photoelectric means for analyzing said spectra during a singletest to produce separate element .3 a hollow anode located in said probehousing Signals FOHeSPOPding to the accumulated and adapted to cooperatewith Said cathode to centration of an internal standard element and atstrike an electric arc in atmospheric air on said least one F F 'fsample surface, thereby generating a sample aer- 90mm] mean recelvlflgseparflte eiemfim 0S0] consisting f atmospheric air and signals andacting on said photoelectric analyzing disrupted Sample particles havingknown 1 means to interrupt the concentration accumulamentalcharacteristics, said aerosol withdrawn each Said identifying elementWhenever thro h id h ll anode f subsequent l said internal standardelement concentration aci d cumulates to a predetermined value, and .4means including lect ical ond ct f .7 means for utilizing at least oneinterrupted idennecting said anode and cathode to an external tifyingelement signal to identify said test matesource of electric current, andfurther including 5 rial without directly comparing the internal stanahose for conducting said sample aerosol away dard signal with anidentifying element signal. from the hollow anode in said samplingprobe,

1. In spectrometric apparatus for identifying a conductive test piece byanalyzing a sample aerosol having sample particles with knowN elementalcharacteristics, the improvement consisting essentially of a samplingprobe comprising: a. a cylindrical probe housing made of electricallyinsulating material and provided with an atmospheric air opening at oneend thereof, b. a cathode mounted at the open end of said probe housing,said cathode including an axial air space and further including an endsurface adapted to contact a sampling surface of said test piece, and a.a hollow anode located in said probe housing and adapted to cooperatewith said cathode to strike a low-voltage electric arc in atmosphericair on said sampling surface, thereby generating a sample aerosolconsisting of atmospheric air and arc-disrupted sample particles, saidaerosol withdrawn through said hollow anode for subsequent analysis. 2.The apparatus of claim 1 wherein said probe housing includes meansassociated with identifying the test piece.
 3. The apparatus of claim 1wherein said cathode is a magnet which enables the sampling probe to bedetachably mounted to test pieces with magnetic properties.
 4. Theapparatus of claim 1 wherein said cathode includes an air passagewaydisposed laterally across the said end contact surface.
 5. The apparatusof claim 1 wherein said anode is adapted to be moved in said probehousing to momentarily contact said sampling surface.
 6. The apparatusof claim 5 wherein said anode is further adapted to be biased andsubsequently withdrawn from the sampling surface to an arc-sustainingposition.
 7. The apparatus of claim 1 wherein said anode furtherincludes a heat sink affixed thereto in the region of the open air spacein said housing.
 8. The apparatus of claim 1 including: d. meansincluding conductors for connecting said anode and cathode to a sourceof electric current and a hose for conducting said sample aerosol awayfrom said sampling probe.
 9. Spectrometric apparatus for identifying aconductive test piece, comprising: a. a hand-held sampling probecomprising: .1 a cylindrical probe housing made of electricallyinsulating material and provided with an atmospheric air opening at oneend thereof, .2 a cathode mounted at the open end of said probe housing,said cathode including an axial air space and further including an endsurface adapted to contact a sampling surface of said test piece, and .3a hollow anode located in said probe housing and adapted to cooperatewith said cathode to strike an electric arc in atmospheric air on saidsample surface, thereby generating a sample aerosol consisting ofatmospheric air and arc-disrupted sample particles having knownelemental characteristics, said aerosol withdrawn through said hollowanode for subsequent analysis, and .4 means including electricalconductors for connecting said anode and cathode to an external sourceof electric current, and further including a hose for conducting saidsample aerosol away from the hollow anode in said sampling probe, and b.flame photometer means connected to means 9.a.4 and adapted to providesaid electric arcing current to said sampling probe, and further adaptedto aspirate said sample aerosol by means of a self-contained inductionburner, said photometer means including photoelectric means foranalyzing the burner flame to determine the concentration of a pluralityof known elements in said sample particles, and further including meansfor indicating the concentration of at least one said element toidentify said test piece.
 10. In spectrometric apparatus for identifyingtest material by generating a sample aerosol having sample particleswith known elemental characteristics and then analyzing said particles,the improvement consisting essentially of flame photometer meanscomprising: a. a housing having an upright chimney, b. a pressurizedbottle of gaseous fuel in said housing, c. an induction burner locatedin said chimney and adapted to aspirate said sample aerosol from itssource while burning said fuel, said burner adjusted to excite sampleparticles in a flame and emit a spectra of radiant energy representing aplurality of known elements in said sample particles, d. photoelectricmeans for analyzing said spectra during a single test to produceseparate element signals corresponding to the accumulated concentrationof an internal standard element and at least one identifying element, e.control means receiving said separate element signals and acting on saidphotoelectric analyzing means to interrupt the concentrationaccumulation of each said identifying element whenever said internalstandard element concentration accumulates to a predetermined value, andf. means for utilizing at least one interrupted identifying elementsignal to identify said test material without directly comparing theinternal standard signal with an identifying element signal.
 11. Theapparatus of claim 10 wherein said control means includes time delaymeans acting on the photoelectric analyzing means for delaying theanalysis of flame spectra for a period corresponding to the timerequired to transport said sample aerosol from its source to saidinduction burner.
 12. The apparatus of claim 10 wherein said testmaterial is steel and said photoelectric analyzing means is adapted toaccumulate the concentration of iron as said internal standard element.13. The apparatus of claim 10 wherein said test material is steel andsaid photoelectric analyzing means is adapted to accumulate theconcentrations of iron and manganese as said internal standard elementand one of said identifying elements respectively.
 14. Portablespectrometric apparatus for on-site identification of a conductive testpiece, comprising: a. sampling probe means including an anode andcathode adapted to strike an electric arc on a sampling surface of saidtest piece and generate a sample aerosol having arc-disrupted sampleparticles with known elemental characteristics, and b. portable flamephotometer means comprising: .1 a hand-carried housing having an uprightchimney, .2 a source of arcing current connected to the anode andcathode in said sampling probe means, .3 a pressurized bottle of gaseousfuel in said housing, .4 an induction burner located in said chimney andadapted to aspirate said sample aerosol from the sampling probe meanswhile burning said fuel, said burner adjusted to excite sample particlesin a flame and emit a spectra of radiant energy representing a pluralityof known elements in said sample particles, .5 photoelectric means foranalyzing said spectra during a single test to produce separate elementsignals corresponding to the accumulated concentration of an internalstandard element and at least one identifying element, .6 control meansreceiving said separate element signals and acting on said photoelectricanalyzing means to interrupt the concentration accumulation of each saididentifying element whenever said internal standard elementconcentration accumulates to a predetermined value, and .7 means forutilizing at least one interrupted identifying element signal toidentify said test material without directly comparing the internalstandard signal with an identifying element signal.
 15. Portablespectrometric apparatus for on-site identification of a conductive testpiece, comprising: a. hand-held sampling probe means comprising: .1 acylindrical probe housing made of electrically insulating material andprovided with an atmospheric air opening at one end thereof, .2 acathode mounted at the open end of said probe housing, said cathodeincluding an axial air space and further including an end surfaceadapted to contact a sampling surface of said test piece, and .3 ahollow anode located in said probe housing and adapted to cooperate withsaid cathode to strike an electric arc in atmospheric air on said samplesurface, thereby generating a sample aerosol consisting of atmosphericair and are-disrupted sample particles having known elementalcharacteristics, said aerosol withdrawn through said hollow anode forsubsequent analysis, and .4 means including electrical conductors forconnecting said anode and cathode to an external source of electriccurrent, and further including a hose for conducting said sample aerosolaway from the hollow anode in said sampling probe, and b. portable flamephotometer means comprising: .1 a hand-carried housing having an uprightchimney, .2 a source of arcing current connected to the anode andcathode in said sampling probe means, .3 a pressurized bottle of gaseousfuel in said housing, .4 an induction burner located in said chimney andincluding a fuel inlet connected to said fuel source, and an air inletconnected to the hollow anode in said sampling probe, said burneradapted to aspirate the sample aerosol and obtain substantially all ofthe combustion supporting gas for burning said fuel from atmospheric airin said aerosol, said burner adjusted to excite sample particles in aflame and emit a spectra of radiant energy representing a plurality ofknown elements in said sample particles, .5 photoelectric means foranalyzing said spectra during a single test to produce separate elementsignals corresponding to the accumulated concentration of an internalstandard element and at least one identifying element, .6 control meansreceiving said separate element signals and acting on said photoelectricanalyzing means to interrupt the concentration accumulation of each saididentifying element whenever said internal standard elementconcentration accumulates to a predetermined value, and .7 means forutilizing at least one interrupted identifying element signal toidentify said test material without directly comparing the internalstandard signal with an identifying element signal.